The invention relates to an apparatus for preparing food, such as a grilling or baking device, comprising a device for heating the air and optionally a grill. Above the unit for heating air, hollow profiles are arranged which can be flowed through by a coolant and whose upper sides are provided with a groove-like arrangement and form run-off grooves for the juices of the food being prepared.
In previously known apparatuses of this kind, the coolant flowing through the hollow profiles, which helps avoid any overheating and the resulting charring of the juices of the food, is either not moved, as a result of which only a low cooling effect is obtained, or there is a forced movement by the hollow profiles which depends on an external energy source such as a battery-operated coolant pump. The latter leads to the consequence that the preparing apparatus will only function correctly when suitable batteries or at least a mains connection are available. Moreover, the installation of a coolant pump leads to additional efforts in production and maintenance.
It is therefore an object of the present invention to provide an apparatus of the kind mentioned above in which a forced movement of the coolant can be realized without any external energy source.
This is achieved in accordance with the invention in that the hollow space within the hollow profiles are formed by at least one, preferably two, chamber(s) which extend continuously in the longitudinal direction of the hollow profiles, whereby the chamber(s) are or can be flowed through by a coolant by means of at least one apparatus to form a coolant flow by using a pressure difference produced in the preparing apparatus.
In this way one or several chambers of the hollow profiles can be flowed through by the coolant without requiring any dependence on any external energy source. The production and maintenance of an apparatus in accordance with the invention is also simplified by the fact that a coolant moving apparatus which is operated by an external energy source can be omitted. The apparatus for forming the coolant flow produces a coolant movement by way of a pressure difference which is produced for example as a result of combustion, a difference in height, difference in density or the like, so that the energies converted in the preparing apparatus for heating for example are used not only for heating the food to be prepared.
A particularly advantageous embodiment of the invention provides that the coolant is a gas, preferably air. As a result, the air sucked in from the ambient environment can be used as a coolant.
A particularly efficient apparatus for forming a coolant flow can be achieved according to a variant of the invention by a suction draft apparatus which allows a relatively strong coolant movement.
It may be provided for in a further embodiment of the invention that the suction draft apparatus is formed by a suction opening of the heating device, that the chamber, or one thereof, of the hollow profiles is in connection at a face-side end with the suction opening via a connecting conduit, and that the opposite other face side of the chamber(s) is open.
Every heating device produces an air movement by the heat emitted by the same. Particularly the suction draft produced during combustion, produces an air flow towards the source of combustion. This suction effect produced during the combustion can therefore also be used for the suction draft effect through the hollow profiles. Moreover, during the supply of a gaseous fuel, the negative pressure produced around the fuel flow can be applied to the coolant movement.
It may be provided in a further embodiment of the invention that the heating device consists of several, preferably rod-shaped gas burners whose gas supply lines extend through the associated connecting conduits, with the air suction opening being disposed within the connecting conduit in the gas supply line.
The gas burners allow a planar heating of the food to be prepared without producing any disturbing combustion exhaust gases.
The gas burner can be provided with gas outlet nozzles which are spaced from one another along the length of the burner, so that gas combustion is obtained which is evenly distributed over the length of the gas burner and an even heating of the food to be prepared is achieved.
In order to prevent any dripping of juices from the food to be prepared onto the gas burner, it can be provided in accordance with a further embodiment of the invention that the rod-shaped gas burners extend parallel to the hollow profiles.
It can be provided according to a further variant of the invention that the suction draft apparatus is formed by an upwardly extending (in the used position) chimney-like flue conduit, that the chambers, or one thereof, of the hollow profiles are connected with the flue conduit at their face-sided end, which flue conduit is open at its upper end, and that the opposite other face-sided end of the chamber(s) is open.
In this way it is possible to use the difference in height between the air inlet position at the hollow profile ends and the upper end of the flue conduit in order to produce a respective suction draft effect on the air flowing through the hollow profiles.
In order to provide a further increase in the flue draft it may be provided according to a further embodiment of the invention that the chimney-like flue conduit is provided with laterally provided air inlet slots. In this way, the warm air of low density which rises from the heating device can enter the flue conduit and reinforce the suction draft acting on the air flowing through the hollow profile chambers.
A preferable further development of the invention provides that the chimney-like flue conduit is provided with a rectangular cross section.
A particularly even distribution of the warm air rising from the heating device can be achieved according to a further variant of the invention in such a way that the hollow profiles, as seen in the used position, are arranged horizontally and the run-off grooves are arranged inclined against the horizontal.
In can be provided for in a further embodiment of the invention that the chamber(s) is or are additionally connected with an apparatus for forced cooling, e.g. an air fan, a coolant pump, or the like. A forced cooling can be achieved in addition to the coolant flow produced by the pressure difference, which forced cooling can be activated in the case of insufficient cooling performance.
Hollow profiles which are easy to produce in a constructional sense and are used to connect with the suction draft apparatus can be achieved in such a way that the two chambers are provided with a superimposed arrangement.
According to a further variant of the invention it can be provided that the heating device is formed by a combustion chamber for filling with charcoal and the suction opening by an air supply opening for the primary air supply into the combustion chamber for the combustion of the charcoal.
The air sucked in from the outside during the combustion of the charcoal flows first through the hollow profiles and thus achieves a measurable reduction in the temperature of the food to be prepared.
The invention relates further to an apparatus for preparing food such as a grilling or baking device, comprising a device for heating air and optionally a grill. Above the device for heating the air several run-off grooves for the juices of the food being prepared are arranged at a distance from one another and preferably in one plane.
Run-off grooves for devices such as grills and baking ovens have long been used to collect the juices of food being prepared and to discharge the same so as to prevent them from reaching the heating device and burning there, as otherwise the vapors produced during the combustion could contaminate the food being prepared with carcinogenic substances.
The run-off grooves are located directly above the heating device and therefore require additional cooling since the juices running off on the grooves could otherwise be overheated and would thus contribute to the production of amounts of carcinogenic substance.
Most of the known cooling apparatuses which are used for this purpose are provided with a very complex arrangement and require a forced movement of the coolant.
It is therefore the object of the present invention to provide an apparatus of the kind mentioned above with which in a technically simple way it is possible to avoid any overheating of the food juices dripping onto the run-off grooves.
This is achieved in accordance with the invention in such a way that between the device for heating the air and the run-off grooves at least one apparatus for deflecting the heated air rising from the device for heating in the direction of the run-off grooves.
As a result, the portions of the rising heated air which would otherwise come directly into heat contact with the run-off grooves and would heat the same are conducted away from the run-off grooves and between the same. As a result of the deflection of the heat flow it is possible to omit any direct cooling of the run-off grooves, or at least any overtemperatures that might occur on the run-off grooves will be so low that the same can be reduced with very simple cooling measures. Moreover, it is possible to prevent with the horizontal arrangement of the deflection apparatus with an inclined arrangement of the hollow profiles that the rising heated air is conducted upwardly along the hollow profiles and that as a result a much stronger heating occurs at the highest position of the hollow profiles than at the positions of the inclined hollow profiles which are beneath the same. An averaging of the temperature progress is thus achieved, so that the food being prepared is not heated with differing intensities.
It can be provided for in a further embodiment of the invention that the apparatus for deflecting the heated air is formed by profiled sheet metal extending parallel to the longitudinal direction of the run-off grooves and beneath the same.
The profiled sheets are thus arranged directly between the heating device and the run-off grooves and deflect the rising hot air away from the lower side of the run-off grooves, so that the same can progress on its way to the food being prepared between the mutually spaced run-off grooves.
It can be provided for in accordance with a further embodiment of the invention that the profiled sheets are arranged, as seen in a cross-sectional view, in the shape of a semi-ellipse divided along its main axis, with the concave portion of the semi-ellipse facing the run-off grooves.
The profile sheet thus provided with a streamlined arrangement allows a highly efficient deflection of the heated air rising from the heating device.
In order to achieve the most comprehensive deflection of the rising heated air, the profiled sheets can extend, as seen in a cross-sectional view, at least over the entire width of the run-off grooves.
As has already been mentioned above, the deflection apparatus allows keeping the rising heated air at least partially away from the run-off grooves and thus achieving a measurable reduction of the groove temperature. In order to achieve an additional cooling it can be provided according to a further embodiment of the invention that hollow profiles which can be flowed through by a coolant such as air or water are arranged on the lower side of the run-off grooves. The coolant that can be conducted through the hollow profiles ensures that a relatively low run-off groove temperature can be maintained, even during any operation of the preparation apparatus in accordance with the invention over prolonged periods of time.
In a particularly advantageous embodiment of the invention it can be provided that the hollow profiles each consist of a basic profile made of floor walls which are arranged V-shaped (as seen in a cross-sectional view) and laterally adjoining vertical walls, and that the run-off grooves having a V-shaped cross section are placed on the vertical walls of the basic profile.
When the hollow profiles are formed according to a further embodiment of the invention of a heat insulating material, a further reduction of the temperature prevailing on the run-off groove is achieved.
In a further embodiment of the invention the heat insulating material can be formed of a ceramic fiber material which is provided with a particularly low thermal conductivity.
To prevent any particles from the rough or fibrous surface of the hollow profiles from reaching the food being prepared, the hollow profiles can be completely encased, with the encasing preferably being formed at least partially by a metal or metal alloy, enamel, glass or a glass mixture, or any temperature-resistant plastic such as teflon or the like.
In order to achieve an effective coolant movement, the hollow profile with the inserted run-off grooves can be in connection at one face-sided end via a connecting conduit with an apparatus for forming a coolant flow by utilizing a pressure difference produced in the preparation apparatus, preferably a suction draft apparatus, and the opposite other face-sided end can be open.
External energy sources for the coolant movement can be omitted as a result of the apparatus used thereby for forming a coolant flow.
It can be provided in accordance with a further embodiment of the invention that the heating device is formed by several, preferably rod-shaped, gas burners whose gas supply lines extend through the associated connecting conduits, with an air-suction opening being provided within the connecting conduit forming the suction draft apparatus in the gas supply line.
The gas flowing into the heating device sucks in air by way of the air-suction opening of the gas supply line and thereby produces an air stream which is conducted through the hollow profiles and causes a cooling of the same there.
In a further embodiment of the invention the gas burners can be provided with gas outlet nozzles which are mutually spaced from one another over its length, thus ensuring a very even emission of gas over the entire length of the gas burner.
A particularly preferable distribution of heat can be achieved with the gas burners in the case when the rod-shaped gas burners extend parallel to the hollow profiles and run-off grooves in accordance with a further embodiment of the invention.
A further variant of the invention can be that the heating device is formed by a combustion chamber for filling with charcoal and the apparatus for providing the coolant flow is formed by an air supply opening into the combustion chamber. The air sucked in from the outside during the combustion of the charcoal first flows through the hollow profiles and achieves in this process a measurable reduction of the temperature of the food being prepared.
For the purpose of a simpler production of the hollow profiles the hollow profiles can be arranged in two parts in accordance with a further embodiment of the invention.
It can be provided according to a further embodiment of the invention that the hollow profiles are each formed by a basic profile consisting of, as seen in a cross-sectional view, two mutually spaced traverses having a V-shaped cross section and two laterally adjoining vertical walls, as well as a run-off groove having a V-shaped cross section which is placed on the walls of the basic profile.
In this way the hollow profiles which are subdivided in the manner of chambers can be produced in a simple way. The run-off groove can be made of a different material, so that the same especially enables a favorable heat contact between the cooling air and the juices of the food being prepared.
In order to prevent the hot air rising from the heating device from overheating the hollow profiles, the hollow profiles can be made of a heat insulating material.
In a further embodiment of the invention the heat insulating material can be formed of a ceramic fiber material which is provided with a particularly low thermal conductivity.
To prevent any particles from the rough or fibrous surface of the hollow profiles from reaching the food being prepared, the hollow profiles can be completely encased, with the encasing preferably being formed at least partially by a metal or metal alloy, enamel, glass or a glass mixture, or any temperature-resistant plastic such as teflon or the like.
In order to achieve an effective coolant movement, the hollow profiles with the inserted run-off grooves can be in connection at one face-sided end via a connecting conduit with an apparatus for forming a coolant flow by utilizing a pressure difference produced in the preparation apparatus, preferably a suction draft apparatus, and the opposite other face-sided end can be open.